SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404b889ef9bb50c7da0d851aab759f7ab2a517bac606c48f7eca137ea3f0142a' 
  AND token = 'BMJmIxfJ7VEcntxck2ZeNOk23iyrJh9FcM3rW4gXRfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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