SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac98c8fc09bbe81dcdfafaeb0f85eef1894cb79da73a6c9c47bf374f86e1f86a' 
  AND token = 't9KOuZpzzthLS8nWvwlM3M7DusS/mGzAWZN+n3/PfGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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