SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '617ab2683c74950da6bf44df997ed41ee933553121cd9602b3ade3d71dd52c6d' 
  AND token = 'EJM+8tbUmod9tPYXeiUZVXFWOn8taOwE9+FdxZqhO14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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