SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6305e9fe36d54a87932635e58b8508b16d57bccb0696f257b396e9659fd793a2' 
  AND token = 'hzHQgFcR38GvVnUWUvn7p6RywQ4nXQY9MtyXG2+vUeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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