SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d1836e949d79087bfb5c151ca4c563d467cd173356783c6865dad27ca021f63' 
  AND token = 'SDFVy0/jmGNsY4OEc0TxEc5qWkvux7QDcsFma7yqc4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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