SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fae959bdf594972856070e56a970e105b2eb99c959f24ed44027af6866947c8b' 
  AND token = 'mXygl/799gfnFLwniQBlKjnlOtOwULBaAwsR8VHAev8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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