SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b67b7bd3fd4213674f5b66cd413507878a025fc5936176fafbaa27a2bc88bb24' 
  AND token = 'FF0VsR9/uv+7i5UQpN5Hj4jRt792TDSPzAJP0eOfiMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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