SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c9b2e9dd7aef48879749df0f113a2a251eac6a63e0428605861e699e5b72b42' 
  AND token = 'HT/lgSgIFchWXjm47RNaa9+STBf/GdyCGZbu27TSLSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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