SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a98af24919fd9e48051b8da1a56c475a37a664037d0307ffb37bf5d82541271' 
  AND token = 'kRY8QskuBq9RXmiyB/w95GzoRJiu4xX0wvJmJmCtxlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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