SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a17a8e637841b525908f758247bae16b79ae5603e9a2b8941989a5b8af45f60' 
  AND token = 'SnTg9/p5HJpQ8KQ7HJc3A+KZwYhqYj6Btm145gahCVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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