SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cedf473a221138c16fcdab55083c4dc994ae6aa24344bccb14924d32b745b51d' 
  AND token = 'aI++i9JtnBbmucKStjIhc8zKgveABEzHtU5+UrbggsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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