SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e2d078ec34e6283f438fdd5445bba40fb618ddc80be9d560504efd575bca654' 
  AND token = '0LJo8cZT24eguHrF/89mYXEGT8H3TDRwJxW3NYCdBfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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