SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a43557be492c3e09f5e35f34c4592eb755ad2509a110b17a081404f90ab4b6e' 
  AND token = 'OfWyaFTVw2UOHtqLQ7zkMmgUXxgGu5iLBT/VyhSvXSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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