SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcd2f9daa216e88d6701165f874abba7556dcd332f7e5a81b5f911f467241fd5' 
  AND token = 'vjtOE/kvvBHTNZnyxUzJnzyJQa6IALO/lDQ1WGueKQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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