SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ec115bce4b255e27abbd5b12de44fb8e4e12554a028006273f29068509309e9' 
  AND token = 'yRuhFVSkPo2GdLYS1Q5JWVIF4hNLBY8Pj8fj7w2mgpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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