SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f010d71ce109b4866c2f2249750a1e69da3ec9020631b8f561e6752df0d45bf' 
  AND token = 'ZWpcQBlootec3lWIyzl05ikqherGT0x4lJAh1bUdIro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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