SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '862b35d66f69c0948f969e0e87a3a9c4a15871b8b4b5db628b2e3cf59bf5e74f' 
  AND token = '3gXA1qjnCY4Ch/5s92zwLkUF751i3++5a06Ngpep5t8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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