SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9b1a94dd5c6ac30e8d410880e9277938ec031409838c0798da68231249421aa' 
  AND token = 'gq+b1gn8Wynx8eDvFgrbqfGQvVHO+sznDKczwWATmlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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