SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aae982ccffeefbd5f972b5e50e763d215905dfc333286d2b5cea22f3d96fcfe4' 
  AND token = 'bIs9IF3OxN55+UAPgIe2O0CuZ5uDRC3XFpZvImFAjEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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