SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16baf074879ae65e37fd5af917e4576fd39f63ff318f58eddfa49d34b83cd21c' 
  AND token = 'UtZtgVoiOkeHwkfYuW5tPldIXVJYhJAINdzNm50OLns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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