SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f946dcaafaec96c1f977f7447c9397daa77f8eed0075d66a97e66741b8b98872' 
  AND token = 'HaKZVgmdJJnQnDm3qW8DRZdGoQbjnk6qkf8wszaJ7Vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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