SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccda8c0e6cce0f0a42145636a3bdb40698ea379cc67c0273bbdddf993699fbda' 
  AND token = 'P8AgDzUmnlSx8AAG1rrVgHbJoCBBYlAYQiahfiF/vFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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