SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a60fbcbdee18240db4521c278aca0abcccf5f1673f91f40c580f475537023d8' 
  AND token = 'SkVrQpluwsYmaqP/nrvBpOVmCUbtDDBaOo/qDk76TRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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