SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69e757ac31ef6c0fd28a7e329316c22954a4e564b4dab5e76fae346c2d50d31f' 
  AND token = 'poPPpJ4HIKGmpAmpjetCheX6RXRsXpUaamooAyw/hcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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