SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e9fb71543a1c8b6cb28d47042e27a3555a2e8451adb31153b9845f6721f794b7' 
  AND token = '7kO3XBnlh5JKLMPiXJvIr8y1C2DbGIgtRIzBOSsEPBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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