SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955300c803428239661123856c813afc959742d4246a656d0f5f6fe9b547bf35' 
  AND token = 's0pUPxZK9oGYNANXzKXdmKWzK9ZNqIMIULgSyT1UOm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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