SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51689a78046f7d2c891530310cf5769c6c464999b74fa2e6b2f942871511c63f' 
  AND token = '8mkc1iHuwPbWr5f7bWfJCpPuB6JWMnEHw1zcJQ2wCzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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