SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dfc6d83f3819d9ae7cdaedf44dc14db489f6d2fb436c6902a436fb2599d6d2a' 
  AND token = 'G59EVHqjG/8r3LNjfIrPSbvlqswhLDg3ygK6SZQ8cV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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