SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b737732dac5def2afbb88d5a3e23cb153e4a8e54157386575a18979bd9e9a19' 
  AND token = 'nV/+7sJdGyLa7vOepqHU7gGqm9V8IGf4sWhZGz0Kv0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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