SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd12776fcfac9266ef8bfe02942dd83805dcb4d97e1db4c7ba2a2793fd539b766' 
  AND token = 'gjNLCmwEhdXH5MmK2i5VGx2P+IFQDmu+/QxcZrhKvrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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