SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f5c4cd2fd96238565e6620e58ef4f3d077ba15548981d1ca221b2354aee6f8' 
  AND token = 'jIfjgDFdQEGouDsvaLz7NxMQp7eJBo+9jl/WeUv4XxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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