SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c501cb6fb1856921936a5a141339f38102c9cb42c464ff72c75f9b40bd7ad6ba' 
  AND token = 'oQSROQTVhHDLTQVXOL3R8IDlu+Bxcutm/MubRbG0NzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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