SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6167b2c6f970f5380081696be2888d1893a5234b47ff7efe17a9118acf080ab' 
  AND token = 'PWVVbxw0iVij0BK3Vnmy7suow0kIPBe1fCu469ZhNKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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