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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '379035f161942a2c4994279f43c89538502dd71fe9558a8ce52aeb2e8567ec1c' 
  AND token = '3U12U1tsHnzKY8O9SPMtqyclz3n+ton9bV+IthQfrSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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