SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b461c127a1d09621550ae58f4c561892995336478d4f4b6b65c96cf0c4178cc' 
  AND token = 'd6wdKpdtwcwUYfRao2pAoPIbJPAGYcErRLPtVk5OYWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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