SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b84ff00fc6e0b011f032aad4b4ecd13d1cae461e5e70d95b186dd665a72ad46d' 
  AND token = 'oWD1ikAmu3Egyv2X8ibTGrNJ0qTbM/nNMPEUbHHGmHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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