SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a2bf6c2074401402c70d967b1ef3a75240e04b1987507e248ebd90eb86901d' 
  AND token = '3NPbDxovOSuzkYo79KEeFnxQgjRssnOhhjZ5p5BQcaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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