SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06e1c139c9c0d5623b61dcaa3598bb732a3a06934db8b2482296de479d866e83' 
  AND token = 'krmFSMC3DznCHdlSWABSElzxlPY1C0zYREOrp3k2RQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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