SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99443ade77e15de5c9717dae4ecef7d13f6d690fce22dd019db4f653643b233f' 
  AND token = 'l8bnRQvT4Afe1weM29YFuodszVJUVsKYHl8j+LvngUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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