SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78691f4b27c18a1535b7d8359c8706fd72caa9028c573d64f2b3be8d77f78ff5' 
  AND token = 'dm9G9ku5odWZD+IlVjmZHMqEUuMBSRV46annYDzGgbw=' 
  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"
    }
  }
}