SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4a0046eb662a3c2079792095064bd5d2d9cdb2f83d6107d2d99099bdda34f30' 
  AND token = '/vejRzCvgnTiq1hunRqVhG6zS+gPVGYhd7wpj+ZRsoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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