SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7aa38a0f731881261914833758efb349e2ee4370563d2ba14405329499308e17' 
  AND token = 'wRJXh9uWBNIpOEFjhZ35+mwmalBm/RLZ002dnhuEZ0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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