SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1ef99f3f6ac2d1b11a12574a7c7f6f545fc8805a1595fbfc4afea4ae83355c5d' 
  AND token = 'l8EjFoi9IDLzgU+YjsxMAKMuGzVX9NLq0vto1xz7pwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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