SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7fa2de7426e1fc3859745a3a46b25784b2bf2e10721b3f906340e683d3995d4' 
  AND token = 'epoQcxTuw+1lXYF1/b6qUnjgChtz6vVsv9WM7lJIzUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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