SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b49e86a7cd344edd9440237fde957f039d0cce07142d328ed29e9cdab28b21ec' 
  AND token = '8IwGsa3MDOiEtFEUznd1ot6rlKjF3RlZAqcyRASLu5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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