SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f179ca4fa37b9bd5b44ff12ddd301eb4201d161d258e5850d06612c474da18b0' 
  AND token = 'r4gDZZfXHo42XZqDZg5QAwVk/PLjXYU96FvujXoKynM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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