SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b37e1ba691cc3bb43b88b136d3878d07a4b51a4ac82f18b96a48846b4caa2922' 
  AND token = 'efZrtlxOsdjLsRx3lJNa16TcdVcmRw0LOCy0HVSGZKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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