SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '405ec0a64368807194160e4fa12d07fe0aeef5e8f99f0ffdb470f79987bb3bca' 
  AND token = 'gwjbvJjEaEztK/wgcw7DL7tCQxfv1DSXj0tueDSCnxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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