SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0617ebc23e35fdbec1efac263c1fcebe4b98fcd6476218a1655c331fe990acb' 
  AND token = 'MnXZVK4H9YcEIzWH0D87ybdQNAGyJOAGOViz2AH7+Bo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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