SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3ea6c9c1745aa3e925267ab80f86fae51ccd797a9a33d13c2a008756eb13094' 
  AND token = 'O70BEjKt18QqezeDgphP7eGlosDUAyxDQuKUyXgEPfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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