SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2055468bcf5213ea29de818d6b5810a5f41405b22335bceb6f90433f0ba31b0' 
  AND token = 'zrUYyxbbjtJY9+WIoL/M0fA48JfdjMJ+HGLbmQQAD80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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