SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eee037a422053b250f28df10dabacaa472f11f3315dcef5fc78f3e8044ba282' 
  AND token = '4ADHv8IsoaLTlvoaYWUDIP8uicQJIUYn4WH/VwksIxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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