SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '801f3e3afeccf3c32097eba9c53678ddf1cd142c204f41f35027955dbea78c6c' 
  AND token = 'xIRu1FvMlvCg4dqNXjEXPbsfaIa/NAEe7yAv+lwbMyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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