SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa4b0c3578816f5e627fd5cac0a378ac862188da09c97a54b15f961b9dfcc91d' 
  AND token = 'CQrnrbVZ3IPSkDe0dUZMWj7F6eaF48Q4B+JyXcReX4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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