SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f274340142b295dc1049c17eba8ebade3d2016fdde2e793daa452d3a91434cc8' 
  AND token = 'RixeFCtV1c40ES57pcuDnmezQ8O/V0Yx1nNgKe9kZhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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