SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e85df07fff1ce7a1d8136893bc098f6a389bffa5fdd0346274884879db3eaec5' 
  AND token = 'b7jkZLaLXvlVZghRzGLTK41fxKxMmwmhNBuewDdOb3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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