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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a93c4966e02700dbe080c91498fd7672afa4cfd5e23432f39dc66f8355d1a9c7' 
  AND token = 'hgrSpxDd1IX3Oh5yIwD/Ad5Kr72RstA/YlR/iJVfmjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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