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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ddcd4103c0c8e65ee22ff3b7d338cc2cfb09df383a6fb98977bc1130c6023c0' 
  AND token = '6qt3UVAgLKUwCDBPoL+rcREr9G+CyV/Bh9Jo9gWtt0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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