SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f1da6a834dd72ffc83ac150fe874426657afdb7a079b892ed552da9cbe743d1' 
  AND token = 'PBT3UHO523hxUi/SC9VIuUVtvpdc5EzdKpQAsgwb3zM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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