SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9b28f5be411d79cb14eba4134dcec40fda9bb8ca1f584fac794d0aaaa0ddf8b' 
  AND token = 'U/2SPeSvKiti3XuOVtyc2R3/KFq4+sGBUOE0pdWb6vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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