SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7f7f84b6d68b450bc59b262e7b27fdd471577e486bf06e042e1ebc2a7cf210f' 
  AND token = 'se0QkQNkgVd17MOQ0ZE7KsaBuMXhhazSEgGyHzfZAkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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