SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '252998de9a654ed335b6e659ed3f1d275377a5e58d6cbb7217656926e506aba0' 
  AND token = '2ZhmG0HvrMZSCGZqJVsw01DGTvvmVNCdMHfu4N0pdFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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