SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3fe0f9d7ef60fc412a66039d550606eb38304be867c40b464fc60d9a2c25e91' 
  AND token = 'moB5REVgGyjRjJHtBX2oxH5ViBNXQJC67FM+bANBPk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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