SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2838c79453a974853db9238ad5ab8c48347566cce4f4657226397b3baaec3fab' 
  AND token = 'qs7c7vAKfEe2UdFTgyO13ODxl5FqCczC+hUAOzevOJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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