SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f77437d0de6d03f92ed68f787ad1d5538deedce085923d819f49c7735addb12d' 
  AND token = 'rPohv0YfgOGOVAijLZ95syfDIVB1u9rh9oU+B9eU13Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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