SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33cda1b4e22252490745e94a9162d33903bbeeded00de32c346ed4fec3c36c50' 
  AND token = 'w/yRJJj2f89MctTULjCjYMBb8TKklaJj9Zta5ZawHgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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