SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c61127b48a47adf35b45368f0b619d871b344f329808ddb7f102d8ebe0b825d0' 
  AND token = 'KJYsVX3kPAdCBPLQL0gNxmhoUkIUoRJ3qZtTGtK82DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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