SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '10e97459d7e3f89e51c9ba0f671025b61687887638e3bcca7fd14954eaf21cee' 
  AND token = 'aFWTyY9q4LQOSYjHmwzmPeBjxaUJ1KQ/BBP0fsCMXCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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