SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21be5a7d33a72fdaecfdc3b2c2e462548dd7ae7a1bf9d6c85fe232fec9826e0b' 
  AND token = 'hMwyc941sygLCnlO2LaEtm9fnVGlq8nbH24o9lRCjQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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