SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f71a8c36560739bc63f8a3675b8f06866d6e459dd4dea3377ee4b801b460f22c' 
  AND token = 'R4zkQBxv9Si1Q4V95ByIWjblDKB8wsqU+fnLoDgTpyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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