SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9de17d973e63e5628d8fc1d0feabb569529b747c2c5ef1fd5c097db7a6fa9387' 
  AND token = 'YteMinXl6BeKmLCzKt4QtOJFVaDHNyQ3EuCm6dYakgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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