SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa576420fb49e9b7f2f23cfd138358a8d83b08a639faaa72eeec88f6cb6b8661' 
  AND token = 'jiowaLnsTrcO6lD3DSiv/B3/CSgI7KMGFTT4grUUkYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}