SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '812805f3bebc3bacd3e2797ded4bf0ea95df2ce708e2a094a80a8cb0a5fc480f' 
  AND token = 'n4FXVWFimkSJtom7tAnj7ngexFoqL9TMUi4tISJGLw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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