SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd2e38bda60c5c5a1b9231894b162d7d1d26bf05de8ad568d117a3b14daae05fa' 
  AND token = 'UpR+SPWQ6k0tDvE4YXVc+Nx+KiwW5oI0t9kmCHw1Qe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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