SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a99f12f9ab0ac8a506d1ce00da14348b1f07b8186108829debbd5296e68f14f' 
  AND token = 'PhQkwENdoZqsMlCxLHq499Vb1pSSlcQPCIntuWT023s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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