SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35401dffbf2428caca1b623ab3203331c7771bfac809bc5aea2d78cd370d4874' 
  AND token = 'Ig7XH+CSrEsJwI+yCNVtMYRk2qCpR8epkfL+4KEGccM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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