SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a16fce06e43156b8f5d9f8192130ab997b48cd0b485690826de3418f20d74cd' 
  AND token = '15B6CZROlAixsi4J/5YsKunnz7CTzPklg7GALPrf8WA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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