SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feafa2750a96773bfec99dd7c39dc79151e93d8a3e6923c6cb1d8b904737e027' 
  AND token = '4zZJwLEOMfc5lA/bbsmx4kIA9DdnokVXXB7h0+JCxvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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