SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a1d829b1952f03e28c45e2440a4ca934e4961b559cb77660f6df10754301307' 
  AND token = 'A7+2jQrKQtajmKxaxTY48xF+pvUMBA72smZNg/YzxSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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