SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df442c50e110fef85e8833f76a72e1f08fe7675686de83bfdf80f8616fb846e9' 
  AND token = 'G2Lbn+gQe+lc1ImKtUxCMzw8o5CZiTJdZfTrbj1XHIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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