SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f567a7eec6ee81806a98771ba1c6b9781d53a83ba6ca2f8ac6b91ad1418d7047' 
  AND token = 'SNBF4vI0sgF09Xu/eQ7ZgDdT6VLee/wKVLUKQdE1Ha0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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