SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23413ecc541161f669fc936bfd067c538bc434a988d1fc8b6145b8786d3f6b5b' 
  AND token = 'Co1kuZDWHw+Zh9GtS0k23zzgInyYuXjdPSEKjG9MA6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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