SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf83991bba06183ecbcbb63f36512daa5822b46838397dbd0136354055dc6ec9' 
  AND token = 'z7dcQqLuLKrJm3+g8gnoj0XsA+e/o/Sob+aa4WMTft4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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