SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6322f380cde27cb58def045155ff4b2f4bf2803eafcf92ac5c4ac996ad163459' 
  AND token = 'YsPHwCYV0WdZEVuHXaEMxDr0jGJMwjUvbL/c8IBIEic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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