SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3429276ffb0929853ee546315fe2c142ae7932ab654b1cc5faf6ad07c3dfb9e0' 
  AND token = 'vQ89/d6q8Jv8XRXLgtmO4DG1WXeo2JUs+b2/IYgCJi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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