SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9f089598157fcdee7aaeaa207468465524806e953126af610a173637f7a8ea6' 
  AND token = 'KgXczDJPXvxOWZ7qKyWS8Wd4h7rCYzOFwsD+BErWQ7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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