SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40f5d0517cc2dc8f1837560be2a7b6dd83196ae3d5476f3f3fbbbb8b46902489' 
  AND token = '86QTjOGgpdCMrYLc1fbb57/GEWz3vWT3w0UNBuSq/qw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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