SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a794a7ed68be27692ffde72c98be56ad48ead1e8c6861695e0e9e88fdd89bd2b' 
  AND token = 'E5V3VgbzuGYLORcTRpjvg8RgVrGVv0OG0cFgcK/SVH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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