SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dab394c73fb2567c4e1c668827193f5c39549663619f95d6a44b8804ee9d0c19' 
  AND token = 'zECpAuOYyFjwI1jTWNOrTEmYyDSSyJecGJuybinYIYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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