SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4686d0f4efe056862953c148ac96092a75f06f8dced1b686f1032b8e8cd02170' 
  AND token = 'u8VYBksFohY46PJ59h/hUdvOqIlEN2iuRdDoCPa4Crg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}