SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6717512fa890510b537f27f309fe896bce54e6dfaca4915bcc3e1208b9a216cc' 
  AND token = 'E1Er5wT03ey2bgcOOdx2w+neTeJ8ZFR5FzlMcnUzC4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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