SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b6b4b092f36e1695d1090a74ad639aaff321bcb0e17bf4da614985c3c1a0393' 
  AND token = 'CdMKCVd/wbpccNPR4C28OBOOpfKboxUIi86X4IwrX+I=' 
  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"
    }
  }
}