SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '03936e5f9a43bc24aa5e966575251e5c6b059b2799393ce87264a9f042a8abcc' 
  AND token = '8gKlyuDRBl5B1m05H5TGes9uCYcv1ogStRCWHkrdkYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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