SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '696474ed1d8d5050bd6fb0150016f7a12a70e266ed30ae20a4ccd02153d5d258' 
  AND token = 'QOK3SV/ENt31DRqlBTa0PQhcnbuaZJsSfsNgbOfALk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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