SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e6dfd7bbdf843556a5975e514aa2052f6f783c8f847cab7121019d20066054e' 
  AND token = 'D1litUTx1p7P7LLqLL8hTIP1xCVRVSTLiBLFX1EgXDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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