SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79a344c45e0d2897f322edb87f345394bd9addfdb727af99473b67e3a1d34ec7' 
  AND token = 'wwM81zqBD8bZsnYTw1D+PVWQAzJUPaKrM181Vi6uCLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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