SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81f1bac326504c812bd5a048684d32e4619803c91383427509c55f0a2106e066' 
  AND token = '7LzNjzEgU84m8whHLIr0giLEzi3DlmwzHOxbKgBRUVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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