SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8929108dbe31afa4bda623d60505e8367644fcc5f25c714ff6a69fe00ab353f5' 
  AND token = '/ZAkNMapEPQbs7cCPUrF3GaClnjWShqzcJS+/RF6pV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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