SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '527a745a4233ccff0942bb19ecf0d18ab64b0a9f9207fa48a7e9444f5f74bb44' 
  AND token = 'U8ijumXHqCbCRs6cZlzlGOk3ntSlWmZM9u//Hq2AmEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}