SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84578d3c7af8c983a04334d53e8190c7f8035b3c05a25bfa6f029b3a1376f5c9' 
  AND token = '7DuYQsYsFMNp9ct30T6Dzp8SU/irvAN1Cg16LVH25uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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