SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b62c8b0420fa9ed99a9a280554d359630fcd2e063acbb1fec8f080c36f4bf786' 
  AND token = 'LENOHHdfxaj/8ZJIx0VFXQUFmbNcfOo3b2ZrJnlLQ2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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