SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3059430cef693776d7060023f442b780c2b69a78d65c1705ddd8be3a957f2270' 
  AND token = 'v/fL6TzMelnVb36YXoElopgyjM1ApfnTfbqYSeuXAuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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