SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1acbea0e068ab5ced55a6d0016e52989518916809b17ef18965b858b3bc4480' 
  AND token = '5VEn6jXKD+UYERSIO2Cbb9XRMadj0ymEqvyB8aDz5OA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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