SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fa9233c5c292a09ab175cc37bd455dd30cf1220f6d0d65b195a5c2254347620' 
  AND token = 'Op+LV0xDU1ZIpFbKvGrDgKyp4jeGn9pEz38QYqnXuTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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