SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd644103d1df0ceecd7895afa7e94b15bc2b353d3ad00bc0fe22652c010d45b4c' 
  AND token = 'FQNdQLt162cYOr10tnH1P6DQTKPjBq8mIqRZYdTFUQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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