SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd949b41a2df5af660ad26d92d8d60d5eebaaecaa1c04e17fe4dce20ed07e4d1d' 
  AND token = 'wQlbWMt/yiKeq334hlwaJ0AqOHFJaxTsbhsVmpH4BKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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