SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0caa5682b21df35ad29ec34300d91541850abf042a89378fb1b9053a22683e7' 
  AND token = 'S8gEZtI1hw5YuMfDPn3KBBJ5AM9uIePt2vQ0dy6dNW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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