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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60928493c3ee50a9e8dd0be87b440a92d31edfe9d6abe38c4cd73eb520b34240' 
  AND token = 'QgHHPw3NIGMe7/AkrhU4ShrCCf1nW5h/LrMScarNTjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}