SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68789dc8fb7bc0d4988f72bdac3c61262e5f4d529152ba5156fa1f50bcee8723' 
  AND token = '4TVhT+3VVPxPx7GyxnrazCSCW5UErjm+GL9LGN4n/qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}