SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ad0cac0071e80b99580922d68f932aac5a537182a2502bfc75d029d08f78a3c' 
  AND token = 'FFPSl4Wb/RvynSmVQup+aHUArdCR4sCoxVQ4GhieugA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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